Donald L Burdette wrote:

> Multiplexing sounds great.  Since you'll have a 7x60 matrix, you'd
> have 60+7 drive pins to work with rather than 420.  However, I don't
> know that a 1/60 duty cycle is reasonable for incandescent lamps.

  It isn't, but then you've got it back to front.  The multiplex for a
7 row by 60 column display is only one in *seven*.  The calculation for
drive voltage is thus much more modest also.

  While in terms of the number of drivers, your alternate suggestion of
28 x 15 is logical, there is much to be said for multiplexing long rows.

  You should be able (if the cost is reasonable) to use integrated
drivers such as the TPIC6595 mounted on the individual modules to drive
the rows at quite modest voltage, while using only seven power
transistors to drive the columns at relatively high current.  These rows
of course chain from one module to the next.

  Don't forget the diode for each incandescent lamp!
--
  Cheers,
        Paul B.